The invention concerns a process and apparatus for the harvesting of crop clusters of tall growing plants, for example corn and sunflowers, whereby the crop cluster or clusters grown on a stalk are separated from the stalk and collected, and thereafter the stalk is chopped up.
To harvest the crop clusters of tall growing plants, such as corn and sunflowers, the clusters have heretofore been separated by gripping the stalk with an intake roll and drawing the stalk through a gathering gap, the width of which is narrower than the diameter of the cluster, so that the cluster is torn off in the course of being drawn in. The crop cluster picked off in this manner is transported by a conveyor to a collector container of the harvester, by means of a chain, a belt or screw conveyor.
For the harvesting of crops of this type, existing agricultural harvesting machines are retro-fitted by the attachment of suitable gathering heads, which for example are driven directly or indirectly by a power take-off shaft. It is known to equip harvesting machines with attachments for crop clusters of this type, in particular for corn, wherein the harvesting machine is provided originally with a transverse drive shaft, that may be equipped with suitable driving means for harvesting attachments to be added. It is possible in this manner to render agricultural machines or harvesters capable of gathering corn in time for the corn harvest. These harvesting attachments grip the corn stalk very deep and draw it through an intake path, with the driven intake rolls being preceded by the intake gap.
German Patent No. 17 57 313 describes a harvesting attachment of this type, comprising intake rolls located on either side of the intake path and driven in opposing directions and a gathering gap through which the plant stalk is being drawn during harvesting. The crop clusters are unable to pass through the gathering gap, so they are torn from the stalk and taken over by a conveyor. The intake rolls are provided with projecting ribs which engage each other during rotation. In the intake area, the plant stalk gripped in this manner is fractured without actually being separated at this fracture location. This fracturing is restricted to the comminution of woody stalk material within the action range of the ribs, wherein continuous fibers (similar to flax breaking) remain preserved.
In order to safely grip the stalk of the plant and draw it through the gathering gap, various suggestions have been presented relative to the configuration of the intake rolls. According to German Patent No. 30 13 689, the rolls have a "star-shaped cross section", with the hollow grooves of one intake roll engaging the projecting ribs of the other intake roll.
According to U.S. Pat. Nos. 3,462,928 and No. 3,174,484, angled sections with pins are set on a shaft with a polygonal, preferably rectangular crosssection, which sections form a similar star-shape and cooperate with each other as in the above-described manner.
Another development is described in U.S. Pat. No. 2,604,750 wherein the ribs are in the form of cutting edges cooperating with an essentially cylindrical counter roll.
To improve the uptake of plants for example lying on the ground, it is proposed in German Patent No. 19 48 511 to rotate helix-equipped noses of the intake rolls at a different (higher) rpm, the intake parts gripping the stalk. For this purpose, the drive shaft of the intake part is in the form of a hollow shaft, through which extends the drive shaft for the nose of the intake roll.
In order to grip stalks of significantly different thicknesses, it is proposed in French Patent No. 1,268,615 to drive at least one of the intake rolls by means of a ball-and-socket joint, so that both of the intake rolls are located at a variable angle to each other and are spaced apart in the area of the nose of the intake roll at a distance corresponding to the stalk diameter.
In all cases, the intake rolls are rotating in opposite directions synchronously at the same rpm, to assure the cooperation of the rolls. A disadvantage here involves the fact that the stalk of the plant is broken but not chopped up or comminuted. To attain the necessary comminution of the stalks, a separate chopper is required, for example according to German Documents GM 67 51 770, GM 79 09 446 or AS 20 05 352.
German Patent 32 13 542 describes a harvester attachment, whereby the stalks are to be cut during their intake movement. For that purpose, a single intake roll is provided for each gathering gap, with the necessary support provided by a partial shrouding surrounding the intake roll. This partial shrouding is additionally equipped with blades pointing in the direction of the intake roll, with the ribs set onto the intake roll having recesses, so that the meshing of the blades in the ribs becomes possible. Aside from problems arising due to the asymmetry of the entry of the plant stalk into the partially shrouded area, squeezing between the ribs and the partial shroud occurs essentially for drawing in the stalk. The blades become effective to cut the stalk only if the stalk is drawn in a relatively pronounced oblique position relative to the intake roll. The squeezing itself only weakens the stalk without cutting the individual stalk sections, with the squeezing process requiring the application of considerable power by the intake roll.
It is, therefore, an object of the present invention to provide a process and apparatus whereby the above-discussed disadvantages are eliminated, and the separation of the individual sections of the plant stalks produced by the breaking or buckling of the stalk after the crop cluster is picked off, is necessarily obtained. A further object is to perform such a process by a modular attachment for harvesting machines, with the process being economical by reducing power requirements and the modular attachment having a simple and easily maintained configuration.